Controlling combustion by flow and pressure



J. M. HOPWOOD.

CONTROLLING COMBUSTION BY FLOW AND PRESSURE.

APPLICATION FILED SEPT-20, 1918. 1,338,926. Patented May 4, 1920.

INVENTOR JOHN M. HOPWOOD, OF DORMONT, PENNSYLVANIA.

CONTROLLING COMBUSTION BY FLOW AND PRESSURE.

Specification of Letters Patent.

Patented May 4, 1920.

Application filed September 20, 1918. Serial No. 254,978.

To all whom it may concern:

Be it known that I, JOHN M. Horwoon, residing at Dormont, in the county of Allegheny and State of Pennsylvania, a citizen of the United States, have invented or discovered certain new and useful Improvements in Controlling Combustion by Flow and Pressure, of which improvements the following is a specification.

The invention described herein relates to the regulation of combustion conditions in furnaces of a plurality of boilers connected to a common header or outlet pipe and consists generally stated in regulating the discharge of gases from each of the furnaces by and in accordance with changes in the rate of flow of steam from and changes in the static pressure of steam in the respective boilers, the regulating of the feed of fuel by and in accordance with variations in the rate of flow and pressure of steam in the common conduit and the supply of air for supporting combustion to each furnace by and in accordance with changes in the pressure of gases in the respective furnaces. The invention is hereinafter more fully described and claimed.

In the accompanying drawings forming a part of this specification is shown diagrammatically a combination of a plurality of boilers and mechanisms for controlling the stack dampers the fuel feeding mechanisms and the feed of air to the furnaces.

In the practice of the invention the regulating mechanisms for the stack dampers for each of the boiler units preferably substantially as shown and described in an application for Letters Patent filed of even date herewith and numbered serially 254,975, have their frames 29 connected by pipes 11 and 12 to the branch pipes D leading from the respective boilers to the common conduit G; The pipes 11 are so connected to the branches that the upper surface of the upper diaphragms of such mechanisms will be subjected to pressures equal to the static pressures of the steam in the boiler, but modified, i. 6., either increased or decreased by the pressure due to the rate of flow of steam through branch pipes. The chambers intermediate the two diaphragms are connected by the pipes 12 to the branch pipes .in such manner that Within this chamber will be maintained a pressure equal to .the static pressure of the steam in the branch pipes.

The under side of the lower diaphragms are subjected to a constant pressure equal to the normal or working pressure desired in the individual boilers, such pressure being applied through the medium of an air cushion within an inverted cup immersed in a liquid contained in a shell 4. As described in the application above referred to, the pipe 12 is connected to this shell by valved pipes so that at the beginning of the operations a pressure may be formed within the shells equal to the normal or working pressure of steam in the individual boilers, and after the establishment of such pressure in the shell, connection between the latter and the pipe 12 is closed. These regulating mechanisms are respectively connected by the cords and the stack dampers 61 controlling the discharge of products of combustion from the furnaces of the respective boilers. In case of a change in the rate of flow of steam from either of the boilers through the branch pipes D, there will be a change in the dynamic pressure on the upper diaphragm of the regulating mechanism connected to such boilers and such change of dynamic pressure will shift a 'lever 15 connected to the upper diaphragm thereby shifting a pilot valve controlling the flow of steam or other fluid pressure to the cylinder 28 so as to shift the piston of such cylinder either up or down in accordance with the direction of change in dynamic pressure above the diaphragm. As described in the application above referred to, the movements of the piston of this cylinder which carries the frame 29, will after a predetermined movement dependent upon the previous adjustment given to the angular rod 32, close such pilot valve and check further movement of the piston and frame 29 in the manner described in said application. Similarly a change of static pressure in the branch pipes will shift the lower diaphragm and through movements of its lever will operate the swinging member 26 thereby opening the pilot valve which will be closed after a predetermined movement of the piston in the cylinder 28 through the action of the angularly arranged rod 33. Thus it will be seen that the stack damper of each of the boilers will be adjusted by and in accordance with any changes in therate of flow of steam through the branch pipes but also in accordance with changes of static pressure in said pipes.

In order to vary the feed of air to each of the furnacesby and in accordance with changes of pressure in the respective furnaces, dampers 64 in the air conduits 65 are connected by any suitable means such as the cords 63 to the frames 18 carried by the pistons of the fluid pressure cylinders 50. The flow of fluid to these cylinders is controlled by pilot valve mechanisms, the movable members of such mechanisms being connected as described in the application above referred to, to arms on rocking shafts carried by pivotally supported frames, said" frames being adapted to be shifted by levers carrying inverted cups having their open ends immersed in a liquid in tanks and into said cups project nozzles connected by pipes 40 to the. respective furnaces. The extent of the movements of the piston in the 'cylinders 50 is determined by the angular positions of bars 58 which engage shoes on swinging members 51-conne'cted to arms 54 on the sameshafts'as the arms connected to movable members of the pilot valve mechaposition of the stack dampers, the frame 29 carried by the piston of the cylinder 28 being connected by a lever to the stem of the roto-reciprocating valve mechanism 67. The movable member ofthis valve mechanism is adapted as described in Letters Patent No. 1,247,217, dated November 20, 1917,

to be shifted longitudinally to open a port so as to permit the flow of steam from the outlet of such valve mechanism through pipes 68 connected to the several mechanisms employed for feeding or controlling feed of fuel to the several furnaces. pipes--11 and 12 leading from the common conduit are connected respectively to the chambers above the upper diaphragm and intermediate the-two diaphragms so that the upper diaphragm will be subjected to the static and dynamic pressure of the stream flowing through the common conduit while the chamber intermediate the diaphragms is so connected to the common conduit that the pressure therein will be equal to' and vary with the static pressure of the stream flowin through the conduit. The operation 0 this mechanism is similar to that as hereinbefore described and also fully set forth in the application referred to, and as its movements are incremental and the feed of fuel to the several furnaces willvary in The accordance with and be proportional to the rate of flow of steam from the boilers and also to changes of pressure of steam in the common conduit (1.

The method of regulating combustion in furnaces as embodied in this invention are especially applicable where a number of stokers are driven from a common source and where the total steam flow passes acommon point in a. main conduit, utilizing the variations of the total steam iflow and variations of steam pressure at such point to obtain regulation of the fuel supply corresponding to changes of load, air supply for combustion by variations of furnace conditions and stack damper by andin accordance with variations of flow and pressure in the discharge conduit from such individual boiler.

Advantages of this method will be apparent where stokers cannot be separately driven and by this means a satisfactory degree of individual control can be secured byregulating the fuel feed by and in accordance with flow,,the air supply for combustion by variations of the furnace pressure, as produced primarily by and in accordance with steam flow from the boiler and by the furnace conditions in each individual unit without depending upon changes of steam pressure.

I claim herein as my invention:

1. The method of regulating combustion herein described which consists in controlling the feed of fuel to a plurality of furnacesof generators of steam, by and in accordance with the rate of flow of steam from all the boilers and the static pressure of the steam, controlling the discharge of products of combustion from the individual furnaces by and in accordance with the 'dynamic and static pressure of the steam flowing from the respective boilers, and controlling. the supply of air to the individual units by and in accordance with the pressure of gases in the respective furnaces, v

2. The combination of a plurality o'ffgenerators of steam, with means controlled by and in accordance with the dynamic and static pressures of steam flowing by a common point from all the generators for regulating the supply of fuel to all the furnaces of the generators, independent means for controlling the discharge of products of combustion from each of the furnaces a (1 controlled by and in accordance with t e dynamic and static pressure of steam fiow lng from the respectlve generators and 1ndependent means for regulating the supply of air for combustion to each of the furnaces controlled by and in accordance with pressure of gases in the'respective furnaces.

3. The combination of a plurality of generators of steam having furnaces with means controlled by and in accordance with generators forregulating the supply of fuel to all of the furnaces of the generators and independent means for controlling the discharge of products of combustion rom each of the furnaces controlled by and in accordancewith the dynamic and static pressure of steam flowing from the respective. gen s v 4. The combination of a plurality of generators of steam havingfurnaces with means controlled by and inaccordance with rny hand.

the dynamic and static pressures of steam flowing by a common point from all of the generatorsfor regulating'the supply of fuel to all of the furnaces of the generators and independent means for r lating the supply. of air for combustion to each of the furnaces'controlled by and in accordance with the pressure of gases in the respective furnaces.

In testimony whereof have hereunto set JOHIN 1m Horwoon 

